Expansion assembly for heat exchanger

ABSTRACT

An expansion assembly for use with a heat exchanger includes a block thermal expansion valve; and a distributor directly connected to the block thermal expansion valve; wherein the distributor comprises a tube having a plurality of openings formed therein.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/969,868, filed Feb. 4, 2020, the contents of which are incorporatedby reference herein in their entirety.

BACKGROUND

Exemplary embodiments pertain to the field of expansion devices. Moreparticularly, the present disclosure relates to an expansion assemblyfor use with a heat exchanger.

Heat exchangers, such as microchannel heat exchangers, are widely usedfor heat transfer in heating, ventilation and air conditioning (HVAC)applications. Traditional thermal expansion valves (TXVs) are notconducive to the microchannel distributor and header geometry, causingthe TXVs to be under utilized in such applications.

BRIEF DESCRIPTION

In one embodiment, an expansion assembly for use with a heat exchangerincludes a block thermal expansion valve; and a distributor directlyconnected to the block thermal expansion valve; wherein the distributorcomprises a tube having a plurality of openings formed therein.

In addition to one or more of the features described herein, or as analternative, further embodiments may include wherein the distributor isconfigured for placement within a manifold of the heat exchanger.

In addition to one or more of the features described herein, or as analternative, further embodiments may include wherein a housing of theblock thermal expansion valve and the distributor are made from the samematerial.

In addition to one or more of the features described herein, or as analternative, further embodiments may include wherein the housing of theblock thermal expansion valve and the distributor are made fromaluminum.

In addition to one or more of the features described herein, or as analternative, further embodiments may include wherein the distributor isdirectly connected to the block thermal expansion valve by at least oneof press fitting, brazing and adhesives.

In another embodiment, a heat exchanger includes an expansion assemblyincluding a block thermal expansion valve and a distributor directlyconnected to the block thermal expansion valve; a first manifold, thedistributor positioned within the first manifold; a second manifoldconfigured to receive refrigerant from the first manifold; and a conduitfluidly connecting the second manifold to the block thermal expansionvalve.

In addition to one or more of the features described herein, or as analternative, further embodiments may include wherein the distributorcomprises a tube having a plurality of openings formed therein.

In addition to one or more of the features described herein, or as analternative, further embodiments may include wherein a housing of theblock thermal expansion valve and the distributor are made from the samematerial.

In addition to one or more of the features described herein, or as analternative, further embodiments may include wherein the housing of theblock thermal expansion valve and the distributor are made fromaluminum.

In addition to one or more of the features described herein, or as analternative, further embodiments may include wherein the distributor isdirectly connected to the block thermal expansion valve by at least oneof press fitting, brazing and adhesives.

In addition to one or more of the features described herein, or as analternative, further embodiments may include wherein the block thermalexpansion valve is directly mounted to first manifold.

In addition to one or more of the features described herein, or as analternative, further embodiments may include wherein the block thermalexpansion valve is directly mounted to the first manifold by at leastone of press fitting, brazing and adhesives.

In addition to one or more of the features described herein, or as analternative, further embodiments may include wherein a housing of theblock thermal expansion valve, the distributor and the first manifoldare made from the same material.

In addition to one or more of the features described herein, or as analternative, further embodiments may include wherein the housing of theblock thermal expansion valve, the distributor and the first manifoldare made from aluminum.

Technical effects of embodiments of the present disclosure includeproviding a block thermal expansion valve and an integrated distributorfor use with a heat exchanger, such as a microchannel heat exchanger.

The foregoing features and elements may be combined in variouscombinations without exclusivity, unless expressly indicated otherwise.These features and elements as well as the operation thereof will becomemore apparent in light of the following description and the accompanyingdrawings. It should be understood, however, that the followingdescription and drawings are intended to be illustrative and explanatoryin nature and non-limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way.With reference to the accompanying drawings, like elements are numberedalike:

FIG. 1 depicts a vapor compression cycle in an example embodiment;

FIG. 2 depicts a heat absorption heat exchanger in an exampleembodiment;

FIG. 3 depicts a cross-sectional view of the heat absorption heatexchanger in an example embodiment;

FIG. 4 depicts the heat absorption heat exchanger in a housing in anexample embodiment;

FIG. 5 depicts an expansion assembly in an example embodiment;

FIG. 6 depicts a block thermal expansion valve in an example embodiment;and

FIG. 7 depicts the expansion assembly mounted to the heat absorptionheat exchanger in an example embodiment.

DETAILED DESCRIPTION

A detailed description of one or more embodiments of the disclosedapparatus and method are presented herein by way of exemplification andnot limitation with reference to the Figures.

Referring now to FIG. 1, a vapor compression refrigeration cycle 20 of aheating, ventilation and air conditioning (HVAC) system is schematicallyillustrated. Exemplary HVAC systems include, but are not limited to,residential, split, packaged, chiller and rooftop, for example. Otherembodiments of this disclosure may be applied to refrigerationapplication. A refrigerant is configured to circulate through the vaporcompression cycle 20 such that the refrigerant absorbs heat whenevaporated at a low temperature and pressure and releases heat whencondensed at a higher temperature and pressure.

Within this vapor compression refrigeration cycle 20, the refrigerantflows in a clockwise direction as indicated by the arrows. Thecompressor 22 receives refrigerant vapor from the heat absorption heatexchanger (e.g., an evaporator) 24 and compresses it to a highertemperature and pressure, with the relatively hot vapor then passing tothe heat rejection heat exchanger (e.g., a condenser or gas cooler) 26where it is cooled by a heat exchange relationship with a cooling medium(not shown) such as air. The refrigerant then passes from the heatrejection heat exchanger 26 to an expansion device 28, wherein therefrigerant is expanded to a low temperature state as it passes to theheat absorption heat exchanger 24. The relatively cold two-phaserefrigerant mixture then passing to the heat absorption heat exchanger24 where it is boiled to a vapor state by a heat exchange relationshipwith a heating medium (not shown) such as air. The low pressurerefrigerant vapor then returns to the compressor 22 where the cycle isrepeated.

Referring now to FIG. 2, an example of a heat absorption heat exchanger24 is illustrated in more detail. The heat absorption heat exchanger 24includes at least a first manifold or header 32, a second manifold orheader 34 spaced apart from the first manifold 32, and a plurality ofheat exchange tube segments 36 extending in a spaced, parallelrelationship between and connecting the first manifold 32 and the secondmanifold 34. In the illustrated, non-limiting embodiments, the firstmanifold 32 and the second manifold 34 are oriented generally along afirst direction and the heat exchange tube segments 36 extend generallyalong a second direction between the two manifolds 32, 34.

Referring now to FIG. 3, a cross-sectional view of an embodiment of aheat exchange tube segment 36 is illustrated. The heat exchange tubesegment 36 includes a flattened microchannel heat exchange tube having aleading edge 40, a trailing edge 42, a first surface 44 and a secondsurface 46. The leading edge 40 of the heat exchange tube segment 36 isupstream of its respective trailing edge 42 with respect to airflow, A,passing through the heat exchanger 24 and flowing across the heatexchange tube segment 36. An interior flow passage of the heat exchangetube segment 36 may be divided by interior walls into a plurality ofdiscrete flow channels 48 that extend over a length of the heat exchangetube segment 36 from an inlet end to an outlet end and establish fluidcommunication between the first and second manifolds 32, 34. The flowchannels 48 may have a circular cross-section or, for example, arectangular cross-section, a trapezoidal cross-section, a triangularcross-section or another non-circular cross-section. The heat exchangetube segment 36 including discrete flow channels 48 may be formed usingknown techniques and materials, including but not limited to, extrudingor folding.

Fins 50 are positioned between the heat exchange tube segments 36. Insome embodiments, the fins 50 are formed from a continuous strip of finmaterial folded in a ribbon-like serpentine fashion thereby providing aplurality of closely spaced fins 50 that extend generally orthogonallyto the heat exchange tube segments 36. Thermal energy exchange betweenone or more fluids within the heat exchange tube segments 36 and an airflow, A, occurs through the outside surfaces 44, 46 of the heat exchangetube segments 36 collectively forming a primary heat exchange surface,and also through thermal energy exchange with the fins 50, which definesa secondary heat exchange surface.

FIG. 4 depicts an exemplary heat absorption heat exchanger 24 positionedin a housing 62. The housing 62 may be part of an internal air handlerof a residential HVAC system. As illustrated in FIG. 4, a bend 60 isformed in each heat exchange tube segment 36 of the heat absorption heatexchanger 24, resulting in a V-shape of the heat absorption heatexchanger 24. In some embodiments the bend 60 has an included bend angle70 less than 90 degrees. In other embodiments the included bend angle 70is between 15 and 45 degrees. The heat absorption heat exchanger 24 maybe placed in a housing 62, with the bend 60 oriented such that the bendis closest to the incoming airflow, A. A first leg 64 of the heatabsorption heat exchanger 24 extends from the bend 60 toward the firstmanifold 32 and a second leg 66 of the evaporator extends from the bend60 toward the second manifold 34. In some embodiments, the heatabsorption heat exchanger 24 is situated in the housing 62 such that thebend 60 is located vertically lower than the first manifold 32 and thesecond manifold 34. The heat absorption heat exchanger 24 may be securedin the housing 62 via the first manifold 32 and the second manifold 34.

A drain pan 72 is located vertically below the bend 60 to capturecondensation from the heat exchange tube segments 36 and fins 50. The Varrangement of the heat absorption heat exchanger 24 encourages thecondensation to run down the first leg 64 and the second leg 66 towardthe bend 60, where the condensation falls from the bend 60. Embodimentsare not limited to a V arrangement of the heat absorption heat exchanger24. The heat absorption heat exchanger 24 may be configured in an “A”arrangement, as or one or more slabs, or other configurations.

FIG. 5 depicts an expansion assembly 100 in an example embodiment thatmay be used with the heat absorption heat exchanger 24. The expansionassembly 100 includes a block thermal expansion valve (TXV) 110 and adistributor 140 connected directly to the block TXV 110. A first port 1of the block TXV 110 receives refrigerant from the heat rejection heatexchanger 26. Reduced pressure refrigerant is directed from port 2 tothe distributor 140. From the distributor 140, refrigerant flows intothe first manifold 32. Refrigerant from the second manifold 34 isprovided to port 3, then to port 4 and then to the suction inlet ofcompressor 22.

The distributor 140 may be formed of a tube 142 having a plurality ofopenings 144 formed therein. Refrigerant from port 2 of the block TXV110 flows along the interior of tube 142 and is emitted though theopenings 144 into the first manifold 32. The distributor 140 may bedirectly secured to a housing of the block TXV 110 using a variety oftechniques, such as press fitting, brazing, adhesives, etc. In anexample embodiment, the housing of the block TXV 110 and the distributor140 are made from a common material, e.g., aluminum.

FIG. 6 depicts a block TXV 110 in an example embodiment. Operation ofthe block TXV 110 occurs through refrigerant expansion/contractionwithin a diaphragm 11. As refrigerant from the second manifold 34 passesover a sensing element 12, expansion or contraction of the refrigeranttakes place causing an activating pin 8 to move a ball valve 6 away fromor closer to a metering orifice 5. This allows more or less refrigerantto enter the first manifold 32. Various pressures within the block TXV110 provide for metering refrigerant to the first manifold 32 throughport 2. A first pressure, F1, is provided by a sealed diaphragm 11 inresponse to a temperature of refrigerant leaving the second manifold 34at port 3. As refrigerant leaving the second manifold 34 passes over asensing element 12 increases in temperature, the refrigerant 9 above thediaphragm 11 expands moving pin 8 downwards pushing ball valve 6 awayfrom the metering orifice 5. A second pressure, F2, is provided by apassage 10 in the block TXV 110 where refrigerant can build up under thediaphragm 11 to act as an opposing pressure against F1 to regulate anamount of refrigerant admitted into the first manifold 32. A thirdpressure, F3, is provided by a spring 7 located under the ball valve 6and acts as an opposing force to move the ball valve 6 towards themetering orifice 5 and to reduce refrigerant flow to the first manifold32.

FIG. 7 depicts the expansion assembly 100 mounted to the first manifold32 of the heat absorption heat exchanger 24 in an example embodiment.Although not visible in FIG. 7, the distributor 140 extends into theinterior of the first manifold 32. A conduit 150 provides fluid pathfrom the second manifold 34 to port 3 of the block TXV 110. The blockTXV 110 may be mounted directly to the first manifold 32 using a varietyof techniques, such as press fitting, brazing, adhesives, etc. In anexample embodiment, a housing of the block TXV 110 and the firstmanifold 32 are made from a common material, e.g., aluminum. The firstmanifold 32 provides a sturdy mounting location for the expansionassembly 100.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the presentdisclosure. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,element components, and/or groups thereof.

While the present disclosure has been described with reference to anexemplary embodiment or embodiments, it will be understood by thoseskilled in the art that various changes may be made and equivalents maybe substituted for elements thereof without departing from the scope ofthe present disclosure. In addition, many modifications may be made toadapt a particular situation or material to the teachings of the presentdisclosure without departing from the essential scope thereof.Therefore, it is intended that the present disclosure not be limited tothe particular embodiment disclosed as the best mode contemplated forcarrying out this present disclosure, but that the present disclosurewill include all embodiments falling within the scope of the claims.

What is claimed is:
 1. An expansion assembly for use with a heatexchanger, the expansion assembly comprising: a block thermal expansionvalve; and a distributor directly connected to the block thermalexpansion valve; wherein the distributor comprises a tube having aplurality of openings formed therein.
 2. The expansion assembly of claim1, wherein the distributor is configured for placement within a manifoldof the heat exchanger.
 3. The expansion assembly of claim 1, wherein ahousing of the block thermal expansion valve and the distributor aremade from the same material.
 4. The expansion assembly of claim 3,wherein the housing of the block thermal expansion valve and thedistributor are made from aluminum.
 5. The expansion assembly of claim1, wherein the distributor is directly connected to the block thermalexpansion valve by at least one of press fitting, brazing and adhesives.6. A heat exchanger comprising: an expansion assembly including a blockthermal expansion valve and a distributor directly connected to theblock thermal expansion valve; a first manifold, the distributorpositioned within the first manifold; a second manifold configured toreceive refrigerant from the first manifold; and a conduit fluidlyconnecting the second manifold to the block thermal expansion valve. 7.The heat exchanger of claim 6, wherein the distributor comprises a tubehaving a plurality of openings formed therein.
 8. The heat exchanger ofclaim 6, wherein a housing of the block thermal expansion valve and thedistributor are made from the same material.
 9. The heat exchanger ofclaim 8, wherein the housing of the block thermal expansion valve andthe distributor are made from aluminum.
 10. The heat exchanger of claim6, wherein the distributor is directly connected to the block thermalexpansion valve by at least one of press fitting, brazing and adhesives.11. The heat exchanger of claim 6, wherein the block thermal expansionvalve is directly mounted to first manifold.
 12. The heat exchanger ofclaim 11, wherein the block thermal expansion valve is directly mountedto the first manifold by at least one of press fitting, brazing andadhesives.
 13. The heat exchanger of claim 6, wherein a housing of theblock thermal expansion valve, the distributor and the first manifoldare made from the same material.
 14. The heat exchanger of claim 13,wherein the housing of the block thermal expansion valve, thedistributor and the first manifold are made from aluminum.